The results of Hardy-Weinberg equilibrium test showed that the APOE genotypes in the T2DM patients (χ2 = 5.957, p = 0.202), T2DM + CAD patients (χ2 = 1.825, p = 0.768), and controls (χ2 = 7.970, p = 0.093) confirmed to the Hardy-Weinberg equilibrium, respectively. Here, APOE is linked to type 2 diabetes mellitus.